Pseudomonas and other non-fermenting Gram-Negative Rods

Name 4 Opportunistic Gram-Negative Organisms “PABS”

1. Pseudomonas species

2. Acinetobacter species

3. Stenotrophomonas maltophilia

4. Burkholderia species

These opportunistic GN organisms are:

-Gram stain + shape

-Environment

-Glucose fermenting?

-Lactose fermenting?

1. Gram-negative bacilli

2. Aerobic/facultative

3. non-lactose fermenting

Patient with leukemia (immunocompromised) complains of urinary urgency, hematuria, and pain with urination (UTI). Shows Gram negative rods. What does this mean?

1. Could be many options → E. Coli is a gram negative rod that causes most UTIs

2. Start something that covers E. Coli

Patient with leukemia (immunocompromised) complains of urinary urgency, hematuria, and pain with urination (UTI). Shows Gram negative rods, non-lactose fermenting? What does this show?

1. Is probably pseudomonas

For Pseudomonas aeruginosa:

-Oxidase +/-

-Does it have any antibiotic resistance?

-Talk about how it survives?

1. Oxidase positive

2. Multiple mechanisms for antibiotic resistance (ampC, other beta lactamase, porin deficiency, efflux pump)

3. Can survive/reproduce in WATER with minimal nutrients

How does pseudomonas look?

1. Blue color of pyocyanin when mixed with yellow tissue

2. Typically produces a green discoloration

Pseudomonas is opportunistic. Are healthy individuals colonized with it?

1. Yes, 2-10% of healthy individuals are colonized with P.aeruginosa

2. Rates in hospitalized patients can be higher

What 4 places do we most find pseudomonas?

1. Eye (contact lens)

2. Wounds

3. Urinary Tract Infections

4. Burns

Mostly see in patients in hospital for a long time or cystic fibrosis patients

True or false? Pseduomonas aeruginosa can produce biofilms?

1. Yes, it deposits in lungs of patients with cystic fibrosis or artificial hearts/pacemakers (plastics)

Name agents that cover pseudomonas aeruginosa?

1. Beta-lactams

   1. Piperacillin-tazobactam, cefepime, cetazidime, meropenem, imipenem

2. Fluroquinolones

   1. Ciprofloxacin, levofloxacin

3. Other agents

   1. Aminoglycosides, polymyxins

62yo patient has history of kidney transplant and has bacteremia. Gram stain is gram negative rods that are lactose non-fermenting? It comes back acinetobacter species. Talk about oxidase, gram stain, and where it contaminates?

1. Oxidase negative

2. Gram negative coccobacilli

3. Contaminates skin

4. Contaminates soaps/disinfectants

Name 3 acinetobacter infections?

1. Bacteremia

2. Respiratory

3. Urinary catheter infections

87yo admitted to hospital for 98 days who received MULTIPLE ANTIBIOTICS and has hospital acquired pneumonia. It is non-lactose fermenting GN rod. What can it be?

Stenotrophomonas maltophilia

Describe stenotrophomonas maltophilia infections:

-Oxidase

-Resistance to abx?

What is first line therapy

1. Oxidase negative

2. Intrinsically resistant to many common antibiotics

3. First line therapy = sulfamethoxazole-trimethoprim

4. Isolated from patients who have received broad spectrum antibiotics

What are 2 stenotrophomonas maltophilia infections?

1. Pneumonia

2. Bacteremia

17yo with cystic fibrosis is being evaluated for respiratory status? They have a non-lactose fermenting GN rod with Gram positive cocci in clusters and has pneumonia. Another rod is mucoid? What is it?

1. Pseudomonas = mucoid rod

2. Cystic fibrosis = Burkholderia species

Name 2 things you would find burkholderia?

1. Pneumonia

2. Wounds

True or false. Meropenem is one of the broadest spectrum antibiotics

True